Process and apparatus for rolling thick plates of glass



March 29, 1932. Y. BRANCART 1,851,803

PROCESS AND APPARATUS FOR ROLLING THICK PLATES OF GLASS Filed Oct. 11,1930 fill en lbr 5am relzazrf Patented Mar. 29, 1932 UNITED STATES YVON.BBANOABT, 01' BONQUIERES, BELGIUM PROCESS AND APPARATUS FOR ROLLINGTHICK PLATES OI GLASS Application filed October 11, 1930, Serial No.487,990, and in Belgium October 18, 1929.

This invention has reference to the production of plate glass and thickglass sheets by rolling. The usual process consisting of directlyrolling the glass to the desired thickness is particularly suitable whenthe glass plate or sheet is not very thick but when a thick plate is tobe obtained it is seen that the surface thereof shows more or less 'deepundulations which render a subsequent grindm ing or polishing treatmentquite indispensable. These undulations are due to the difference in thecontraction of the two sides of the late, one of which i. e. that cominginto contact with the receiving table cools down relatively quickly,while the other, which is exposed to the atmosphere, remainscomparatively hot, the more so the greater the thickness of the plate.

The object of my present invention is to avoid as 'much as possible theproduction of such undulations and to obtain in a single operation plateglass of any desired thickness having a smooth surface on both sides. Tothis end I first roll separately two or more sheets of glass of lessthickness than the plate to be produced,then I bring them together andunite them by rolling to form the final thick plate. The difference inthe temperatween both sides of a plate of glass thus formed of two ormore layers, is greatly reduced on account of the fact that thecomponent sheets,while still hot enoughto unite with each other, havealready undergone substantial cooling when they are so rolled together.In fact the undulations on the surface of such a composite plate are nomore accentuated than those which would appear on the surface 46 of oneof the thin component sheets if these were rolled separately. I havefound that when the process is carefully carried out, only a thin lineacross the edge of the finished plate shows the place where thecomponent sheets have united, and '4 his does not in any way impair thetransparency of the glass.

In carrying out my improved process I may use any suitable type ofdouble multiple lass: rolling train, such as is used for the rmanufacture of armoured or wire glass for example, but I proceed in suchmanner that ture, and consequently in the contraction, be

the separate amount of glass are only in contact with the rolls for averyshort'time before .they are united into a single sheet or plate. Itherefore use upper rolls of small diameter and larger lower rolls. Imay separately and simultaneously feed the top pairs of rolls with glassfrom difl'erent sources, but

I preferably feed them with glass from the same source which isconveniently a kidney shaped receptacle adapted to simultaneously tofeed two sheets side by side.

I have in the accompanying drawing diagrammatically illustrated onemethod of carrymg out my invention.

In the said drawing I have shown two upper rolls of small diameter a andtwo lower rolls 6 of larger diameter which rolls 7) are adapted toco-operate both with each other and with the upper rolls a. Above therolls a is a partition 0. Under the lower rolls 6 is a movable table (1for receiving the finished plate 6 formed by the union of two sheets fwhich are rolled first separately between the rolls a and b, thentogether between the two large cylinders 72. In order separately to formthe two glass sheets f, glass is simultaneously poured from two ordinaryreceptacles 9 into the spaces between the rolls a. and b on each side ofthe apparatus, whereas, if it is desired to form the two sheets from thesame glass, at single kidney shaped receptacle is used, the cavity ofwhich is placed astride the partition 0 so that the glass is poured intwo substantially equal streams forming each one of the sheets.

It however should be understood that my invention is not limited to theuse of a rolling train as illustrated nor is it restricted to theuniting of two or any other given number of component sheets.

I claim:

1. In a process of forming thick glass plates free from undulations,simultaneously pouring masses of molten glass from a receptacle on bothsides of a partition onto the 95 upper surfaces of two (go-operatingrolls of large diameter, simultaneously rolling said masses of glassbetween said rolls and smaller rolls and immediately thereafter unitingthe said separately rolled masses and simultane- 1 ously rolling themtogether between said rolls f of large diameter.

- 2. In apparatus for rolling molten glass, the combmation of akidney-shaped receptacle, a substantially Vertical partition extendmgaxially .u'nder said receptacle, a pair of large rolls adapted toco-operate with one another, each of said rolls being adapted to receiveglass supplied from said receptacle on f 10 one side of said partition,and two small rolls l above said large rolls adapted each to cooperatewith oneof said lar e rolls..

a x YVON RAN CART.

